Hand portable cutting devices



June 22, 1965 G. w. MOUNT 3,139,997

HAND PORTABLE CUTTING DEVICES Filed April 25, 1963 ATTORNEYS UnitedStates Patent 3,189,997 HAND PORTABLE CUTTING DEVICES George W. Mount,'76 Leyden Road, Greenfield, Mass. Filed Apr. 23, 1963, Ser. No. 275,1154 Claims. (ill. 39-228) This invention relates to motorized cuttingdevices and particularly to hand portable electrically driven cutters.The object of the invention is to provide an improved cutter havingeither a scissors type action, a slicing type action, or a combinationof the two actions.

A principal object of the invention is to provide a cutting device inwhich an extremely small motor may be utilized for effective cuttingaction by reason of the mounting of the movable blade of the device. Anadditional advantage gained by the blade mounting is a more effectiveuse of an extremely thin blade such as blades of the safety razor type.A further object of the invention is to provide an arrangement in acutting device of the class described which may readily be adaptedeither for a straight scissors type action or for slicing or slidingknife type of action.

These and other objects and advantages of the invention will be apparentfrom the following description and accompanying drawings in which,

FIG. 1 is a side elevational view of a cutting device embodying theinvention;

FIG. 2 is a front end View thereof;

FIG. 3 is a view similar to FIG. 1 with parts cut away and showing amodification of the invention adapted for a sliding knife and scissoraction; and

FIG. 4 is a view on line 4-4 of FIG. 1.

In the embodiment of the invention illustrated by FIGS. 1, 2 and 4 thedevice is shown as a straight scissors type of cutter. A cylindricalmotor casing encloses a motor (not shown) having a shaft 12 (FIG. 2)extending from one end of the casing. The shaft is provided at its outerend with an enlarged drive collar 14 having an eccentrically placedheaded cam or pin 16 fitted to extend from the outer face of the collar.In this embodiment a link 18 is journaled on the pin 16 as will be laterdescribed.

Extending rearwardly from the casing 10 is a carrying handle 20 withgrip for manipulating the device. At the rear end of the hand grip arelead wires 22 for connection of the motor to a suitable source ofelectricity. This supply may be rechargeable batteries or plug-in toconventional power line as desired. A push button 22 for on-ofiiactuation of a motor switch (not shown) is located at the inner end ofthe grip for convenient thumb operation.

A frame plate 24 is mounted at the end of the casing 10 from which shaft12 extends. Arcuately shaped spacer piece 26 supports the plate memberin spaced relation to the end of the casing and the assembly is fixed tothe casing by mounting screws as at 28. Frame plate 24 includes arearwardly and downwardly directed panel or web having at its lower edgea forwardly extending foot member generally indicated by the numeral 30.

The foot 30 is disposed in spaced underlying relation to the shaftcollar 14 and has a shearing edge 32 provided by a replaceable blade 34fixed in a slot 36 of the foot and projecting slightly above its uppersurface. Edge 32 constitutes the stationary edge of the device. As shownby FIG. 4 the foot is formed from an integral extension 38 of the plate24 together with a foot piece 40 joined to the extension as by screws42. The slot 36 is formed by a rectangularly recessed portion of piece40 facing the opposing wall of extension 38. Blade 34 is held againstthe recessed wall of slot 36 by the shoulders of mounting screws 44which are threaded into the foot piece.

Also mounted in slot 36 is the lower end of a movable cutting edge, suchas that of a blade 46 pivoted on a pin 48 which extends through pieceand is removably threaded into panel 38. The slot accommodates the widthof the two blades so that the cutting edges are in adjacent relation forgood cutting action. The edge of blade 46 is angularly directed upwardlyof the lower edge 32 and in the upper portion of the blade a pivotalconnection is made with the lower end of link 18.

As will appear from FIG. 1 rotation of the motor shaft will drive theeccentric pin 16 to rapidly oscillate the blade 46 on its pivot 48. Thiscutting action is of the scissors type.

In the embodiment of FIG. 3 a movable blade 50 is shown directly pivotedon eccentric pin 16. With the direct connection and resulting action onblade movement slot 52, preferably open ended, is provided in the lowerend of the blade parallel to the cutting edge 51 of the blade. The openended slot straddles a pin 54 set in opposing walls of slot 56 of thefoot member 60. Since the blade 50 reciprocates longitudinally footmember 60 is of a greater depth than member 30 of the embodiment ofFIG. 1. Slot 56 thus completely encloses the lower end of blade 50 forits full linear stroke. A lower stationary edge is provided by a blade62 fixed in slot 56 by mounting screws 64 similarly to the blade 34 ofFIG. 1.

While the action of blade 50 on rotation of the motor shaft will benoted as including a rocking movement it will be seen that the angularrelationship of the blade, pin 54 and pin 16 will provide primarily aslicing or sliding action on a workpiece fed against the cutting edge51. This is in contrast to the scissors type of action which isdeveloped in the embodiment of FIG. 1. And it will be furtherappreciated that by changing the location of pin 54 relative to pin 16,as by moving it rearwardly on foot 60, a different angular relationshipcan be established so as to impart more of the scissors movement to thecutting action in this form of the device.

In each of the embodiments of the device there is preferably included ashoe plate fixed at the opposite end of the motor casing 10. This is inthe form of a skid element to assist in supporting and guiding thedevice on platform surfaces during a cutting operation. The lower edgeof the shoe as best seen from FIGS. 2 and 3 is slightly elevated fromthe lower edge of the foot. This is for the purpose of accommodating thethickness of a piece of work which is to be cut. In FIG. 2 there isshown a cloth piece 72 in position for cutting, the shoe riding on theupper surface of the cloth in spaced relation to the foot while thelatter underlies the cloth for moving the blades along a desired line ofcut. The foot has a tapered tee for sliding under a fiat work piece andat 74 the edge of the web of plate 24 is beveled immediately behind themovable blade for smoothly engaging a cut edge.

It is to be noted that the scissors type of device as in FIG. 1 has ashort stroke and that an extremely small light motor will be able tooscillate a light blade rapidly and effectively. This type may be usedadvantageously in cutting yard goods or other fabrics such as upholsteryfabrics and paper products such as cardboard etc. The blade is held ateach end and with the outer end being forced down on the work during thecutting stroke an extremely thin type of blade can be used to advantage.As will be appreciated the blades as shown are easily replaceable whenworn. With stouter blades closely Woven carpet fabrics can be readilycut.

The sliding type of device as in FIG. 3 is useful for cutting toughermaterials such as stiff linolenms, foam rubbers, and other plastic sheetmaterials or the like. For

stiffer and more brittle sheet materials a serrated or saw tooth type ofcutting edge on the movable blade may be preferable and it will, ofcourse, be appreciated that where desired the lower blade may be omittedand a shearing edge provided by the edge of the slot in the foot of theframe.

It will also be realized that for maximum cutting efficiency theadjacent sides of the stationary and movable blades should preferably bein flat face to face contact with each other and the cutting edges inclose contact at the interconnection of these two edges. Thus duringmovement of the upper blade one cutting edge will Wipe past the other.Accordingly, the replaceable blades are preferably provided with knifeedges having a bevel formed on the outside edge only. Where blades withknife edges bevelled on both sides are used, the lower stationary blademay be suitably canted in the slot of the foot-for contact at theintersecting edges.

What I claim is:

1. A hand portable cutting device for sheet materials and the likecomprising a frame having a foot member and a shearing edge on the uppersurface of the foot, a motor fixed to said frame in elevated relation tothe foot and having an armature shaft positioned transversely thereofwith crank means at the end of said shaft overlying said shearing edgein spaced relation thereto, a blade member having upper and lower endswith a cutting edge therebetween, said blade extending upwardly frombelow said shearing edge and at its lower end having a pivotal mountingconnection on said foot underneath said shearing edge and at itsopposite upper end being connected to said crank means for theapplication of driving movement of the blade at said upper end.

2. The structure of claim 1 in which said crank means comprises aneccentric drive pin member fixed on said armature shaft and a linkpivotally connected at one end to said pin and at the other end to saidupper end of the blade member. s V

3. The structure of claim 1 in which said crank means comprises aneccentric drive pin member fixed on said armature shaft, and said bladeis pivotally connected at its upper end to said drive pin, the pivotalmounting of the lower end of said blade on the foot being a pin and slotconnection.

4. The structure of claim 1 in which the motor is provided with casingto one end of which the said frame is attached, said casing at the otherend of the motor hav- References Cited by the Examiner UNITED STATESPATENTS 1,288,858 12/18 Fcgley et a1. 30238 X 1,651,176 11/27 Bannon30-273 X 1,693,301 11/28 Kopp 30-238 1,755,511 4/30 Miller 30228 2,277,42 3/42 Kuhlman 30-238 2,731,721 1/56 Traurig 30249 2,934,822 5/60 Docken30-247 WILLIAM FELDMAN, Primary Examiner.

MYRON C. KRUSE, Examiner.

1. A HAND PORTABLE CUTTING DEVICE FOR SHEET MATERIALS AND THE LIKECOMPRISING A FRAME HAVING A FOOT MEMBER AND A SHEARING EDGE ON THE UPPERSURFACE OF THE FOOT, A MOTOR FIXED TO SAID FRAME IN ELEVATED RELATION TOTHE FOOT AND HAVING AN ARMATURE SHAFT POSITIONED TRANSVERSELY THEREOFWITH CRANK MEANS AT THE END OF SAID SHAFT OVERLYING SAID SHEARING EDGEIN SPACED RELATION THERETO, A BLADE MEMBER HAVING UPPER END LOWER ENDSWITH A CUTTING EDGE THEREBETWEEN, SAID BLADE EXTENDING UPWARDLY FROMBELOW SAID SHEARING EDGE AND AT ITS LOWER END HAVING A PIVOTAL MOUNTINGCONNECTION ON SAID FOOT UNDERNEATH SAID SHEARING EDGE AND AT ITSOPPOSITE UPPER END BEING CONNECTED TO SAID CRANK MEANS FOR THEAPPLICATION OF DRIVING MOVEMENT OF THE BLADE AT SAID UPPER END.